President Hassan Rohani says Iran will do all it can to secure a deal with world powers on its disputed nuclear program.

Rohani told a business forum in Ankara, Turkey, on June 10 that "Iran will do its best for a final deal with the P5+1," made up of the five permanent UN Security Council members -- Britain, China, France, Russia, and the United States -- plus Germany.

Rohani's statement came as Iranian and U.S. officials met behind closed doors for a second day of talks in Geneva on Tehran's nuclear program, which the West suspects has military goals.

After the first day of talks, the U.S. State Department had warned that "tough choices" needed to be made.

Iranian Deputy Foreign Minister Abbas Araqchi said the first day of discussions had taken place in a "positive and constructive" atmosphere.

Araqchi also said later that Iran will hold bilateral talks with other P5+1 members in coming days in order "to come to a better understanding of the differences."

U.S. State Department spokeswoman Marie Harf said the "wide-ranging" session ran for over five hours.

The two sides are trying to bridge differences ahead of another round of full negotiations between Iran and six world powers.

Those negotiations are aimed at reaching a full agreement to replace an interim accord secured last November, under which Tehran shelved some nuclear work in return for limited relief from sanctions.

Iran and the world powers are facing a July 20 deadline to secure a final deal.

However, Araqchi was quoted on June 9 by Iranian media as saying that negotiations could be extended for another six months if no deal is reached by July 20.

Reports say talks between Iran and the so-called P5+1 -- Britain, China, France, Russia, the United States and Germany -- have bogged down over the scope of Iran's uranium-enrichment program.

Western officials say Iran wants to maintain a program far beyond what is needed for civilian nuclear power stations.

Iran has repeatedly denied Western charges it is secretly developing nuclear weapons.

The next round of talks between the P5+1 and Iran is scheduled in Vienna starting on June 16 and scheduled to end on June 20.

A French diplomatic source quoted by the Reuters news agency said officials from France and Iran will meet on June 11 to discuss the Vienna negotiations.